The present invention relates to a tubular shaft motor and pump assembly for the transmission of gases, liquid or mixed fluids. 2. Description of the Related Art
Traditional fluid transmitting devices can be generally divided into two different types, namely, the impeller pump and the cascade pump.
FIG. 6 illustrates a conventional impeller pump. The impeller pump includes an impeller (B) inside a delivery pipe (A); and a shaft (C) connected to the impeller (B) and passing through the delivery pipe (A) to connect with the motor (M). The motor (M) transmits power to the shaft (C) which, in turn, causes the impeller (B) to turn. The fluids flow up as indicated by the arrows in FIG. 6. With larger transmitting capacity and shorter lift, this type of device is usually used in the discharge of fluid, irrigation, etc.; but has the following shortcomings:
1. The coaxial relationship between the motor (M) and the shaft (C) is critically important and must be maintained precisely in this structure. Any imprecision will cause the motor (M) to not work smoothly. In order to avoid this problem, universal joints, gear couplings or flange joints have been added between the motor and the shaft. This, however, not only increases production cost but also increases the likelihood of machine break-down.
2. The conventional impeller pump is also noisy because of noise generated by the contact between external moving parts.
3. The conventional impeller pump also requires a large mounting base for installing the motor (M) and pump. Consequently, space in the installation area becomes limited.
4. To assure that the impeller pump runs properly, a certain gap must be maintained between the blades and the delivery pipe (A). Such gaps create small vacuum areas which result in a significant loss in overall efficiency. In the case of an electrically powered motor, this loss in efficiency leads to wasted electricity.
FIG. 7 illustrates a conventional cascade pump. The cascade pump includes a rotary vane (E) inside a housing (D), and a shaft (F) in the center of the rotary vane (E) extending outside the housing (D) and connecting with the motor (M). When rotational power supplied by the motor (M) turns shaft (F) and the rotary vane (E), fluids at the intake (D1) are sucked into the housing (D) and are turned by the rotary vane (E) and subsequently output from the discharge (D2). Because of deflector (D3), fluids are expelled out through discharge (D2) in a vertical direction as indicated by the arrows shown in FIG. 7. With higher lifting ability and smaller transmitting capacity, this type of pump is usually used in tall buildings and mansions but has the following disadvantages:
1. As in the case of the impeller pump, a precise coaxial relationship must be maintained between the motor (M) and the shaft (C). This not only increases production cost but also the possibility of machine break-down.
2. In addition, the conventional cascade pump is noisy because of noise generated by the complicated structures and devices.
3. The conventional cascade pump also suffers from significant losses because of the circular flow and the friction developed within the pumps. In particular, the fluid flow is in a circular direction after the fluid is sucked into the intake (D1). There is consequently a long transmitting distance, as well as friction between the deflector (D3) and the inner wall of the housing (D). This, in turn, creates significant losses in efficiency during the transmitting process.